Vice Admiral The Hon. John Byron, RN (8 November 1723 – 10 April 1786) was a Royal Navy officer. He was known as Foul-weather Jack because of his frequent bad luck with weather.
Byron was the son of William Byron, 4th Baron Byron and Frances Berkeley. He joined the navy in 1731, accompanying George Anson on his circumnavigation as a midshipman. On 14 May 1741, Byron's ship, HMS Wager, was shipwrecked on the coast of Patagonia, and the survivors decided to split in two teams, one to make its way by boat to Rio de Janeiro, the other, John Byron's, to sail North and meet Spaniards. He described his adventures and the Wager Mutiny in The Narrative of the Honourable John Byron (1768), which sold well enough to appear in several editions. These experiences form the basis of the novel The Unknown Shore by Patrick O'Brian, which closely follows Byron's own account.
Byron was commissioned captain of HMS Siren in December 1746.
In 1760 he was in command of a squadron sent to destroy the fortifications at Louisbourg, which had been captured by the British two years before. In July of that year he defeated the French flotilla sent to relieve New France at the Battle of Restigouche.